The overall objectives of this research are to develop monoclonal antibodies to distinct determinants on human prostate carcinoma-associated antigens (PCAA) in order to: (1)\develop double determinant immunoassay (DDIA) to study the shedding of PCAA by prostate cancer cells in vitro and in vivo; (2)\study the cellular heterogeneity of human prostate tumor cell lines and tissues; and (3)\analyze the molecular heterogeneity of PCAA. In the next year, efforts will be focused on the following activities: (1)\production of new antibodies to distinct determinants of PCAA will be continued using new immunization procedure, e.g., by injecting mice with purified PCAA covered with one antibody to the antigen; (2)\the DDIA will be developed with the antibodies that have already been obtained in the past year that show preferential activity for prostate carcinoma cells to study the shedding of PCAA by cultured prostate tumor cells; (3)\the same antibodies will be applied in immunohistochemical study of human prostate tissue using peroxidase staining methods; and (4)\the antibodies will be used in immunochemical analysis of the PCAA by two-dimensional gel analysis, i.e., isoelectrofocusing and SDS polyacrylamide gel electrophoresis. (AG)